AU671528B2

AU671528B2 - Jointing element

Info

Publication number: AU671528B2
Application number: AU59331/94A
Authority: AU
Inventors: Michael Henry Choake
Original assignee: SANDIE HOLDINGS Pty Ltd
Current assignee: SANDIE HOLDINGS Pty Ltd
Priority date: 1993-04-07
Filing date: 1994-04-07
Publication date: 1996-08-29
Anticipated expiration: 2014-04-07
Also published as: AU5933194A

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION For a Standard Patent

ORIGINAL

9..

0 Name of Applicant: Actual Inventor(s): Address for Service: MICHAEL HENRY CHOAKE MICHAEL HENRY CHOAKE WRAY ASSOCIATES, Primary Industry House, Terrace, Perth, Western Australia, 6000.

239 Adelaide Attorney code: WR 0* 0 *0e* Invention Title: "Jointing Element" Details of Associated Provisional Application No: PL8189.

The following statement is a full description of this invention, including the best method of performing it known to me:- -1 I Ir -2- THIS INVENTION relates to a jointing element.

It is usual to provide expansion joints in cast concrete such as driveways, cycle paths and foot paths to accommodate thermal contraction and expansion, and thus minimise cracking.

A system for forming expansion joints in cast concrete is disclosed in Australian Patent No. 604612. This patent is directed to a keyed joint plate assembly which comprises a joint plate and plurality of stakes to support the joint plate in position during the casting operation. The joint plate has coplanar vertical top and bottom sections interconnected to a parallel rearwardly spaced central section 10 by rearwardly convergent upper and lower inclined sections. Holes are formed in the upper and lower incline sections in vertical alignment to accommodate S* •stakes, and wedges are provided for engagement between the central section of the plate and each stake. A resilient expansion strip may be provided on or adjacent the top section of the plate to further accommodate thermal expansion.

In practise, this expansion strip is placed in position during the casting and screeding operation and subsequently removed and the resulting cavity filled with resilient sealant.

The keyed joint plate assembly of Patent No. 604612 has not proved to be altogether satisfactory in use for various reasons one of which is that it is very labour intensive to install.

The present invention seeks to provide a novel jointing element which provides a useful alternative to the keyed joint plate assembly described above.

In one form the invention resides in a jointing element for formation of an expansion joint in cast concrete, comprising a base portion for resting on the ground or other foundation surface onto which the concrete is cast, an upper portion and an intermediate portion between the base portion and the upper portion, the base portion extending transversely of and beyond the upper portion

I

-3to presert a relatively broad surface for contact with the ground or other foundation surface and the intermediate portion comprising a first section offset from the upper portion and extending transversely of and beyond the upper portion in a direction opposite to the base portion to allow engagement of a support with the first section without the support contacting the upper portion or the base portion.

With this arrangement, the base portion defines a projection onto which concrete can be placed during the casting operation. In this way, the projection extends below the cast concrete and provides stability for the jointing element.

Pr-ferably the upper portion is generally upright. Furthermore, the upper portion may have a pair of opposed faces, with the base portion extending beyond at least one of the opposed faces of the upper portion. Conveniently, the opposed faces are planar faces.

I The intermediate portion may have a first section which extends to one side of 15 the upper portion so that in use sections of concrete on opposed sides of the jointing element are interlocked.

onigeeetaeitrokd :".The intermediate portion may have a second section which extends to the other side of the upper portion.

•The intermediate portion may have two or more of said first sections extending to said one side of the upper portion to provide the jointing element with faces for S resting against a support such as a removable holding bar.

S The various sections of the intermediate portion may cooperate to define a corrugated formation. ThM corrugated formation may be of any suitable shape such as a sinusoidal wave form, a square wave form or a saw-tooth wave form.

The top edge of the upper portion may be provided with a rib. The rib may extend to both sides of the upper portion.

The jointing element is preferably of one-piece construction and is conveniently formed of plastics 1 0 material.

In another form the invention resides in a jointing element foi formation of an expansion joint in cast concrete, comprising a base portion for resting on the ground or other foundation surface onto which the concrete is cast, an upper portion, and an intermediate portion between the base portion and the upper portion, the intermediate portion having a section which extends to one side of and beyond the upper portion to in use interlock sections of concrete on opposed sides of the jointing element.

The intermediate portion may have a further section which extends to the other side of the upper portion.

The intermediate portion may have two or more of said sections extending to said one side of the upper portion to provide the jointing element with faces for resting against a support such as a removable holding bar.

The various sections of the intermediate portion may cooperate to define a corrugated formation. The corrugated formation may be of any suitable shape such as a sinusoidal wave form, a square wave form or a saw-tooth wave form.

5 In another form the invention resides in a method of forming a joint in cast concrete using a jointing element as defined hereinbefore.

The invention will be better understood by reference to the following description of several specific embodiments thereof as shown in the accompanying drawings in which: Fig. 1 is a perspective view of a jointing element according to the first embodiment; •go ei Fig. 2 is a side view of the jointing element; I10 Fig. 3 is a side view showing the jointing element in position during a concrete casting operation; Fig. 4 is a front view of the jointing element shown in the position in Fig. 3; Fig. 5 is a rear view of the jointing element in the 15 position shown in Fig. 3; Fig. 6 is an end view of a jointing element according to a second embodiment; and Fig. 7 is a schematic view illustrating various other possible embodiments of the jointing element.

20 The embodiments shown in the drawings are directed to a jointing element for formation of expansion joints in slabs of cast concrete, particularly for use as pathways and cycle ways.

The jointing element 10 of the first embodiment comprises a length of plastics material having a base portion 11, an upper portion 13 and an intermediate portion 15 between the base portion and the upper portion. The upper portion 13 is upright in use, and includes a pair of opposed planar faces 16 and a rib 17 at its top edge. The rib 17 protrudes on both sides of the upper portion 13 and is intended to prevent or at least inhibit the entry of foreign matter such as dust and sand into the completed expansion joint.

6 The base portion 11 extends transversely of the upper portion 13 to one side thereof, terminating at a free edge 12. The base portion 11 presents a broad surface 19 for resting on the ground or other foundation surface on which the concrete slab is cast.

The intermediate portion 15 comprises first and second sections 21 and 22 which are in spaced apart relation and which extend to one side of the upper portion 13. Between the first and second sections there is a third section 23 9o*ee* S" 10 which extends to the other side of the upper portion 13.

The first, second and third sections 21, 22 and 23 respectively cooperate to define a corrugated formation which in this embodiment is sinusoidal. The corrugated formation serves to interlock the sections of the concrete slab on opposed sides of the expansion joint. The interlocking arrangement is such that the joint can be separated in the event that it is necessary to repair a damaged section of the concrete slab.

The jointing element is supplied as a length which can be cut according to the requirements of a particular job. The jointing element is positioned between formwork which defines the sides of the slab to be cast and is located such that the free edge 12 of the base portion 11 faces the section of the slab to be cast and the top face of the rib 17 is at the level of the upper face of the slab. The broad face 19 presented by the base portion 11 allows the jointing element to sit firmly on the ground or other foundation surface for the slab. Support elements such as a holding bar assembly 27 are positioned on the side of the jointing element opposite the section of the slab which is to be cast; that is, on the side of the jointing element opposite to the free edge 12 of the base portion, as best seen in Fig. 3. The first and second sections 21 and 22 7 respectively of the intermediate portion 15 provide faces which bear against the holding bar assembly, also as best seen in Fig. 3 of the drawings. Once the jointing element is in position, concrete can be poured into the form work and a vibrating screed is used to vibrate and level the slab. The screed vibrates easily over the joint. The holding bar assembly is then removed while the concrete is still wet and the concrete is trowelled smooth. The holding bar assembly is subsequently used to support a similar expansion joint at the end of the next section of the slab. Once the holding bar assembly has been removed, the concrete slab is trowelled and finished leaving the surface level and smooth, with no ridges at the expansion joint. It will be noted that the base portion 11 extends under the section of the slab being cast.

The jointing element provides a joint between sections of the slab which can accommodate thermal contraction and expansion and so minimise cracking. The corrugated formation serves to interlock neighbouring sections of the 20 slab at the expansion joint in a way which can accommodate normal loadings but which can also be separated to allow damaged sections of the slab to be repaired.

*e Fig. 6 of the drawings illustrates the configuration of a jointing element according to a second embodiment.

Fig. 7 of the drawings illustrates (in broken lines) various other shapes which may be employed for the jointing element. It will be seen from this drawing that the corrugated formation can be of a square wave form or a sawtooth wave form. It should, however, be appreciated that various other configurations are possible for the intermediate section.

8 While the invention has been described in relation to several specific embodiments, it should be understood that it is not limited thereto and that various alternations and modifications may be made without departing from the scope of the invention.

Claims

1. A jointing element for formation of an expansion joint in cast concrete, comprising a base portion for resting on the ground or other foundation surface onto which the concrete is cast, an upper portion and an intermediate portion between the base portion and the upper portion, the base portion extending transversely of and beyond the upper portion to present a relatively broad surface for contact with the ground or other foundation surface and the intermediate portion comprising a first section offset from the upper portion and extending transversely of and beyond the upper portion in a direction opposite the base portion to allow engagement of a support with the first section without the support contacting the upper portion of the base portion.

2. A jointing element according to claim 1 wherein the base portion extends to one side of the upper portion to define a projection onto which concrete can be placed during the casting operation. S 15 3. A jointing element according to claim 1 or claim 2 wherein the upper portion is generally upright.

4. A jointing element according to any one of claims 1 to 3 wherein the upper portion has a pair of opposed faces. o A jointing element according to claim 4 wherein the opposed faces are 20 planar faces.

6. A jointing element according to any one of claims 1 to 5 wherein the intermediate section has a first section which extends to one side of the upper portion so that in use sections of concrete on opposed sides of the jointing element are interlocked.

7. A jointing.element according to claim 6 wherein the intermediate portion has a second section which extends to the other side of the upper portion. n~l=i~l~j Y~Util~~

8. A jointing element according to claim 6 or 7 wherein the intermediate portion has two or more of said first sections extending to said one side of the upper portion for engagement with the support.

9. A jointing element according to claim 8 wherein the support is a removable holding bar. A jointing element according to any one of claims 7 to 9 wherein the first and second sections of the intermediate portion cooperate to define a corrugated formation. ooeoo

11. A jointing element according to claim 10 wherein the corrugated formation a. 10 is a sinusoidal wave form. A jointing element according to any one of claims 1 to 11 wherein the upper portion has a top edge configured as a rib. a a:

13. A jointing element according to claim 12 wherein the rib extends to both :sides of the upper portion. 15 14. A jointing element according to any one of claims 1 to 13 wherein the jointirng element is of one-piece construction. A method of forming a joint in cast concrete using the jointing element according to any one of claims 1 to 14.

16. A jointing element substantially as herein described with reference to the accompanying drawings. -11

17. A method substantially as herein described with reference to the accompanying drawings. DATED this fourth day of June, 1996 MICHAEL HENRY CHOAKE Applicant WRAY ASSOCIATES Perth, Western Australia Patent Attorneys for the Applicant e. e o e **e eaee ease' ABSTRACT A jointing element 10 for formation of an expansion joint i-n cast concrete, comprising a base portion for resting on the ground or other foundation surface onto which the S concrete is cast. The jointing element 10 further "comprises an upper portion 13 and an intermediate portion between the base portion and the upper portion. The base portion extends transversely of and beyond the upper portion to present a relatively broad surface for contact with the ground or other foundation surface. o 6